If you use Oracle Database Server then forensics might be a concern for you. NGSSoftware released three new papers (listed below) that you might find very useful.
Oracle Forensics Part 1: Dissecting the Redo Logs
Oracle Forensics Part 2: Locating Dropped Objects
Oracle Forensics Part 3: Isolating Evidence of Attacks Against the Authentication Mechanism
You can download copies at the NGSSoftware database security site.